Use is being made on increasingly large scale and in many different fields of bar codes, for instance in supermarkets but also for stock control and the like. Using bar codes stock control is improved, transit speed is increased and more accurate specifications of supplied goods can be given to the buyer, such as the consumer.
It is still a regular occurrence however that a bar code is not decoded at the first reading by a scanning device. This can be due for instance to a differing width of a bar or space, as well as to the inhomogeneity of the paper on which the bar pattern is printed, noise occurring for instance as a result of ambient influences or caused by analog electronics, thermal noise and/or variations in the scanning equipment used.
Known scanning devices, for instance making use of laser beams, of CCD (Charge Coupled Devices) image recorders and/or making use of RF (Radio Frequency) induction and methods for decoding bar codes are widely described in the patent literature, for instance in the non pre-published European patent applications 952015097 and 952021939 of applicant.
Also known from EP 0439682 is a method and device according to the precharacterising part of claims 1 and 8 respectively.